Rapid determination of single substitutional nitrogen Ns concentration in diamond from UV-Vis spectroscopy

Abstract

Single substitutional nitrogen atoms [Formula: see text] are the prerequisite to create nitrogen-vacancy (NV) centers in diamonds. They not only serve as the electron donors to create the desired NV− center and provide charge stability against photo-ionisation but also are the main source of decoherence. Therefore, precise and quick determination of [Formula: see text] concentration is a key advantage to a multitude of NV-related research in terms of material improvement as well as applications. Here, we present a method to determine the [Formula: see text] concentration based on absorption spectroscopy in the UV-Visible range and fitting the 270 nm absorption band. UV-Visible spectroscopy has experimental simplicity and widespread availability that bear advantages over established methods. It allows a rapid determination of [Formula: see text] densities, even for large numbers of samples. Our method shows further advantages in determining low concentrations as well as the ability to measure locally, which is highly relevant for diamonds with largely varying [Formula: see text] concentrations in a single crystal. A cross-check with electron paramagnetic resonance shows high reliability of our method and yields the absorption cross section of the 270 nm absorption band [Formula: see text] cm−1 ppm−1 (in common logarithm) or [Formula: see text] cm−1 ppm−1 (in natural logarithm), which serves as a reference to determine [Formula: see text] concentrations and makes our method applicable for others without the need for a known [Formula: see text]-reference sample and calibration. We provide a rapid, practical, and replicable pathway that is independent of the machine used and can be widely implemented as a standard characterization method for the determination of [Formula: see text] concentrations.

Single photon emission from in situ created nitrogen-vacancies in chemical vapor deposition grown single crystal diamond

“…Figure 2 shows optical images and corresponding UV-visible (UV-vis) absorption spectra of highly transparent and large area CVD grown SCD samples. UV-vis absorption spectroscopy is employed to determine the substitutional nitrogen (270 nm) concentration in diamond samples up to ∼10 ppb level [11]. The FWHM of Raman peak (1331.5 cm −1 ) reveals the amount of random stress present in the sample and the presence of directional stress may give rise to a shift or splitting of the Raman line [13,14].…”

“…Figure2shows optical images and corresponding UV-visible (UV-vis) absorption spectra of highly transparent and large area CVD grown SCD samples. UV-vis absorption spectroscopy is employed to determine the substitutional nitrogen (270 nm) concentration in diamond samples up to ∼10 ppb level[11]. Figure2(d)displays the transparency of diamond samples in the visible range and the appearance of 270 nm absorption peak exhibits the presence of substitutional nitrogen.…”

Productivity of Concentration-Dependent Conversion of Substitutional Nitrogen Atoms into Nitrogen-Vacancy Quantum Emitters in Synthetic-Diamond by Ultrashort Laser Pulses

“…(2) Laser irradiation resulted in the rise of optical absorption in the range of 400-550 nm by 6-10% (Figure 2b), which should be multiplied by D 0 /D ~10-20 to evaluate true local changes. Such changes could be potentially related to different radiation-induced centers like pure vacancy V 0 (410-430, 741 nm/GR1-GR8), N2V (ZPL at 440.3 nm), NnI (441.6 nm), 2I2V (469.9 nm/TR12 ), I2V (503.5 nm/3H) and 2NV (503.2 nm, H3), NV 0 (575 nm) and NV − (637 nm) [7,[20][21][22][23][24][25][26][27] with their UV-red absorption [7,18,19], potentially emerging in the broadband PL spectra (Figures 5 and 6). Since the initial [C y ] ≈ 1.2 × 10 19 cm −3 and [C c ] ≈ 3.7 × 10 18 cm −3 , the concentration of I-V pairs for their conversion should be high too, providing these different anticipated aggregated forms of N, I, and V species; (3) PL intensities over the entire acquired range of 400-750 nm increase with the increasing initial [C] in the colorless and yellow regions, and exhibit saturation versus laser exposure, indicating the exhausting of C-centers.…”

“…The experimental sample was an inhomogeneously colored synthetic (high-pressure, high-temperature, HPHT) Ib-type diamond hexagonal plate (hexagon side-4 mm, thickness D0 ≈ 0.5 mm) (Figure 1a), possessing exceptionally C-centers with their local concentrations [Cy] ≈ 70 ppm or ≈1.2 × 10 19 cm −3 (yellow region) and [Cc] ≈ 22 ppm or ≈3.7 × 10 18 cm −3 (colorless region), according to FT-IR microspectroscopic measurements, [C(ppm)] = 25 × α1135 (cm −1 ) [7] or [C(ppm)] ≈ (21-22) × α1130 (cm −1 ) at higher [C][15] in range of 500-4000 cm −1 (Figure1b), using a FT-IR spectrometer Optics IFS-125HR with a microscope Hyperion 2000 (Bruker, Billerica, MA, USA) and a FT-IR spectrometer Vertex V-70 with a microscope Hyperion 1000 (Bruker, Billerica, MA, USA).The HPHT plate was characterized by an ultraviolet(UV)−near-IR (190-1100 nm) transmission spectrophotometer SF-2000 (OKB Spektr, St. Petersburg, Russia) (Figure2a) and an ultraviolet(UV)−near-IR (350-900 nm) transmission microscope-spectrometer MFUK (LOMO, St. Petersburg, Russia) (Figure2b). For both the colorless and yellow zones, there is a sharp absorption edge near 600 nm, with the absorption coefficient gradually rising toward 270 nm (the absorption band of C-centers[7,18,19]). The band is clearly visible for the colorless region, but it is not fully distinguishable for the yellow region (see also FigureS1in the Supplementary Materials file for linear scale plots).…”

Absorption and birefringence study for reduced optical losses in diamond with high nitrogen-vacancy concentration

“…The microwave frequency was set to 9.84 GHz, and the P1 concentration was determined using the built-in spin-counting feature, from the acquisition software (xEPR). UV–Vis measurements follow our methods paper [ 40 ]. We extracted the absorption band at 270 nm from the other spectral features, determine the absorption coefficient plots via equation ( 2.2 ) and the concentration of P1 centres via the absorption cross section determined from multiple reference samples.…”